Ban Kapas is an erect, slightly branched shrub 2-3 m in height. The leaves are ovate, 10-20 cm long, somewhat 3-lobed or nearly entire, green and nearly smooth on the upper surface, somewhat hairy beneath, broad and heart-shaped at the base and pointed at the tip. The flowers are large, and borne in threes in the apex of the branches or at the axils of the leaves. The calyx is green, with 5 pointed lobes united below the middle. The corolla is bell-shaped, 6-8 cm long, yellow, and dark-purple at the center. The capsules are ovoid, and about 3 cm long, with 4-5 valves.